260 Miocene Strata. 



The surface of the plain, according to Mr. Pengelly, 

 consists of sandy clay, which contains a large number of 

 angular and subangular stones lying unconformably on 

 the Miocene strata, which consist of numerous beds of 

 sand, clay, and, in the northern part, of lignite. Accord- 

 ing to Mr. Horace Woodward, the total thickness of 

 these strata may be from 200 to 300 feet. The whole 

 of these Miocene beds give the impression that they 

 were originally deposited in a lake hollow, the sands 

 and clays having been derived from the waste of the 

 neighbouring Greensand and the granite of Dartmoor, 

 while the vegetable matter that now forms the lignites 

 consisted of stems and leaves of trees, fruits, ferns, 

 &c., which were drifted by the streams of the time into 

 the lake, where they got water-logged and sank, to be 

 buried in the gradually accumulating strata. 



In the northern part of the area, where the Bovey 

 coal (lignite) occurs, near Bovey Tracey, the beds, ac- 

 cording to Mr. Pengelly, dip at an angle of 12J- , about 

 15 south of west, while according to Mr. Woodward, fur- 

 ther south they dip much in the same direction about 5. 

 The lignite division of the strata is separated from the 

 more southern clayey part of the area by a fault, pro- 

 bably of about 100 feet. In the opinion of Mr. Pen- 

 gelly and Mr. Woodward, the strata south and east of 

 the fault belong to an upper part of the series, which 

 originally spread over that part of the strata in which 

 the beds of lignite are found, having since been removed 

 by denudation. 



When we consider the effect of the fault, and also of 

 the inclination of the strata, it is evident that the 

 formation as originally deposited, must have spread 

 beyond its present limits in the direction of the sur- 

 rounding hills, and that the old lake probably washed 



